Computer games and arcade games often feature animated, user-controlled characters which represent human users and which appear human or humanoid. These characters are referred to as “avatars”. Currently, there is growing interest in creating an on-line community in which people are represented by avatars and can interact with each other in a virtual world (a simulated environment) through their avatars in a realistic manner. Ideally, the virtual world will provide sufficient “richness” so that the avatars can interact with each other and their virtual environment in much the same way people interact in the real world. The availability of the Internet makes such a virtual world potentially accessible to millions of users. Such a virtual world may impact many areas of everyday life, including communications, entertainment, commerce, and education, to name just a few. The usefulness and success of an avatar-based virtual community will depend largely on the sophistication and realism of the avatars and the ways in which they can interact. Users will want to use and participate in such applications only if their avatars are realistic and sophisticated in their capabilities.
While users of a virtual world may want to engage in various activities, such as racing a car or flying around the world in a plane, one of the most compelling and desired activities is communicating with other users. Thus, one of the principal features common to known three-dimensional (3D) worlds is the ability for different users of the world to communicate with one another, through text chat. In known 3D worlds, conversation has been presented in a way that is no different from online text conversations without a 3D world, using instant messaging and email, where text is presented in a 2D window, separating it from the 3D world. Known 3D virtual worlds do not provide avatars with body language, facial and gestural expression, or 3D symbolic visuals for user-to-user communication. To provide users with a rich user experience in a virtual world, it is desirable to make avatars' faces and bodies important components in user-to-user avatar communication, as in the real world.